Locations:
Other House Items Shop - Centaur 21
Other House Items Shop - House Building
Price: 25 Gold
Sellback: 7 Gold
Description: Who knows what hatched out of this huge egg!
Thanks to mturf and Sasuke_kool1.

", it wouldn't get common, it would get 1%Drop rarity. however the few exceptions are the really obvious (and rather rare) ones; broken/weird/dumb/crazy. if there is something like a giant tentacled fish

completed the previous quest.
The final key is called the Key of the Void. I've tried to aVOID this key, so far but I've seen it. The purple-black metal seems to writhe and slither in your hand. If you bring